Reversible data hiding in dual stego-images using frequency-based encoding strategy

摘要

Reversible data hiding methods can embed secret data into multimedia to prevent attacks from hackers. Reversible data hiding methods based on multiple stego-images have been proposed extensively in recent years. This type of method can embed large amounts of secret bits into several stego-images. However, data embedding may cause serious distortion of stego-images. To solve this problem, Lu et al. proposed a center-folding strategy to reduce secret digits to narrow down the distance between the original pixel and the stego pixel in 2015. Although the center-folding strategy works well, it can still be improved. In their proposed scheme, the maximum secret digit seriously damages the image quality of the stego-image. If the maximum secret digit occurs often, then the visual quality of the stego-image decreases quickly. In this paper, we propose a frequency-based encoding method to solve this problem. The secret digit that occurs most frequently is encoded as the minimum absolute digit, thereby decreasing the frequency and level of modification. Experimental results showed that the proposed method can achieve a greater peak signal-to-noise ratio value than previous methods, thereby confirming that the proposed method is effective.